https://old.reddit.com/comments/1qsljlw

My friend who attended said, “a daytime protest 5-10k strong organized by unions consisting of liberals, moms, teachers, nurses, and many many children and old people lead to a completely unprovoked onslaught of pepper bullet, flash bangs, and an absolutely astonishing amount of tear gas. It was terrifying, with that many people we were in serious danger of a stampede or being crushed. My eyes started to water and I got separated from my mom so I doubled back to find her, and suddenly the gas was so thick I couldn’t see at all, I felt like I was gonna shit my pants and throw up.”

Obviously law enforcement, apparently (according to other comments) federal - which would include ICE - did this.